fe_compute_data.h

一个用来实现偏微分方程中网格的计算库

// $Id: fe_compute_data.h 2501 2007-11-20 02:33:29Z benkirk $

// The libMesh Finite Element Library.
// Copyright (C) 2002-2007  Benjamin S. Kirk, John W. Peterson
  
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
  
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
  
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA


#ifndef __fe_compute_data_h__
#define __fe_compute_data_h__

// C++ includes
#include <vector>


// Local includes
#include "libmesh.h"

// Forward declarations
class EquationSystems;
class Point;

/**
 * class \p FEComputeData hides arbitrary data to be passed to and from
 * children of \p FEBase through the \p FEInterface::compute_data() 
 * method.  This enables the efficient computation of data on
 * the finite element level, while maintaining library integrity.
 * -- With special finite elements @e disabled (like infinite elements),
 * this class wraps the return values of @e all shape functions
 * from \p FEInterface::shape() in a \p std::vector<Number>.
 * -- With enabled infinite elements, this class returns a vector of physically
 * correct shape functions, both for finite and infinite elements.
 */
class FEComputeData
{
public:


//------------------------------------------------------
// Conventional FEComputeData
  /**
   * Constructor.  Takes the required input data and clears
   * the output data using \p clear().
   */
  FEComputeData (const EquationSystems& es,
		 const Point& pin) :
    equation_systems(es),
    p(pin)
  { 
    this->clear(); 
  }


  //----------------------------------------------------
  // Input data
  /**
   * Const reference to the \p EquationSystems object
   * that contains simulation-specific data.
   */
  const EquationSystems& equation_systems;
  /**
   * Holds the point where the data are to be computed
   */
  const Point& p;



  //----------------------------------------------------
  // Output data
  /**
   * Storage for the computed shape function values.
   */
  std::vector<Number> shape;


#if defined(ENABLE_INFINITE_ELEMENTS) && !defined(USE_COMPLEX_NUMBERS)
  /**
   * Storage for the computed phase lag
   */
  Real phase;

#endif

#ifdef ENABLE_INFINITE_ELEMENTS
  /**
   * The wave speed.
   */
  Real speed;

#endif

#if defined ENABLE_INFINITE_ELEMENTS && defined(USE_COMPLEX_NUMBERS)
  /**
   * The frequency to evaluate shape functions
   * including the wave number depending terms
   */
  Real frequency;

#endif

  /**
   * Clears the @e output data completely.
   */
  void clear () ;


  /**
   * Inits the @e output data to default values, provided
   * the fields are correctly resized.
   */
  void init () ;
};


#endif // #ifndef __fe_compute_data_h__